# Load all modules implementing a behaviour in escript

**URL:** <https://forum.elixirforum.com/t/load-all-modules-implementing-a-behaviour-in-escript/33348>\
**Category:** Questions\
**Tags:** deployment, escript, introspection\
**Created:** [July 25, 2020, 3:43pm UTC](https://forum.elixirforum.com/t/load-all-modules-implementing-a-behaviour-in-escript/33348 "2020-07-25T15:43:15Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![elvanja](https://forum.elixirforum.com/user_avatar/forum.elixirforum.com/elvanja/32/17393_2.png) [@elvanja](https://forum.elixirforum.com/u/elvanja)\
**Post date:** [July 25, 2020, 7:22pm UTC](https://forum.elixirforum.com/t/load-all-modules-implementing-a-behaviour-in-escript/33348/2 "2020-07-25T19:22:58Z")

</div>

Update, a slight modification, without using `Mix` is marginally better:

```elixir
  defp available_modules_with_behaviour(behaviour) do
    # compiled from `Mix.Task.run("loadpaths", [])`
    build_path = Path.expand("_build/prod")
    app_path = Path.join([build_path, "lib", Atom.to_string(:external_data_sync)])
    Path.join(app_path, "ebin")

    # Fetch all .beam files
    Path.wildcard(Path.join([Path.expand("_build/prod"), " **/ebin/** /*.beam"]))
    # the rest is the same
    ...
  end

```

This works, but in reality it’s only because `lib` is right where the code expects it. So it looks like the related `lib` module isn’t included in the escript.

I tried several ways to include all code from `lib` in that escript related module, no luck. Not even `:ok = Application.ensure_started(:app)` seems to be working. Even just aliasing those modules doesn’t work, they need to be explicitly used. This seems to work after all:

```elixir
  @scenarios [
    SyncData1
    SyncData2
    SyncData3
  ]

  # and before requesting modules that implement `Scenario` behaviour
  Enum.each(@scenarios, &Code.ensure_loaded?(&1))

  # now finding those modules works
  all_scenarios = available_modules_with_behaviour(Scenario)

```

So I guess this is all about how to actually include the main app into escript. If it’s even possible…

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